Dave,

There are some hardware differences between the 2 models.   I*think* 
there may be either a a new or different roofing filter involved.  The 
original  had some bands as up conversion and some as down conversion, 
and the new model  is all down conversion.  This is just all from memory.

As has been said, a totally different menu structure.   The 2 models are 
different enough that the Kenwood  control software is different for the 
2  models.  I also know that there  are 4 setting choices  for the amp 
keying in the SG as opposed to 3 choices for the S.   Don't know what 
the 4th one does.

  There was a recent firmware   addition to the 590S in the past few 
weeks.  It allows  both NB1 and NB2 to be used at the same time.

The big upgrade in firmware was several months ago  with V. 2.0

Here is a link to the page with a list of all firmware changes.   Quite 
a few for v. 2.0:

http://www.kenwood.com/i/products/info/amateur/ts_590/ts590_update_e.html

The update to v. 2.0 is easy and worth it in my opinion.


73, Steve  KW3A
On 8/4/2015 8:31 PM, Dave Basden wrote:
> I was laboring under the apparent misconception that applying the
> firmware update to a TS-590S made it equivalent to a TS-590GS.  From
> recent discussions on the list I guess this isn't the case.  What do
> you gain from the firmware update and what do you not gain compared
> to a TS-590GS?
>
> 73,
>
> Dave, W7OQ
>
>
>